121100561 has 2 divisors, whose sum is σ = 121100562. Its totient is φ = 121100560.

The previous prime is 121100531. The next prime is 121100563. The reversal of 121100561 is 165001121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120670225 + 430336 = 10985^2 + 656^2 .

It is an emirp because it is prime and its reverse (165001121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121100561 - 2²⁶ = 53991697 is a prime.

Together with 121100563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (121100563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60550280 + 60550281.

It is an arithmetic number, because the mean of its divisors is an integer number (60550281).

Almost surely, 2^121100561 is an apocalyptic number.

It is an amenable number.

121100561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121100561 is an equidigital number, since it uses as much as digits as its factorization.

121100561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60, while the sum is 17.

The square root of 121100561 is about 11004.5700052296. The cubic root of 121100561 is about 494.7457266318.

Adding to 121100561 its reverse (165001121), we get a palindrome (286101682).

The spelling of 121100561 in words is "one hundred twenty-one million, one hundred thousand, five hundred sixty-one".